03_objects.rb

require 'pg'
require 'pry'

class Artist
  CONN = PG.connect(dbname: 'chinook')
  attr_accessor :id, :name

  def self.new_from_row(row)
    id = row["id"]
    name = row["name"]
    new(id, name)
  end

  def self.find_by_name(name)
    sql = <<-SQL
      SELECT *
      FROM artists
      WHERE name=$1
    SQL

    CONN.exec_params(sql, [name]) do |result|
      result.map do |row|
        self.new_from_row(row)
      end
    end
  end

  def self.find(id)
    sql = <<-SQL
      SELECT *
      FROM artists
      WHERE id=$1
      LIMIT 1
    SQL

    CONN.exec_params(sql, [id]) do |result|
      row = result.first
      self.new_from_row(row)
    end
  end

  def initialize(id, name)
    @id = id
    @name = name
  end

  def insert
    sql = <<-SQL
      INSERT INTO artists (name)
      VALUES ($1)
      RETURNING id
    SQL
    @id = CONN.exec_params(sql, [self.name]).first["id"]
  end

  def update
    sql = <<-SQL
      UPDATE artists
      SET name=$1
      WHERE id=$2
    SQL
    CONN.exec_params(sql, [self.name, self.id])
  end

  def save
    if self.id
      update
    else
      insert
    end
  end

  def destroy
    sql = <<-SQL
      DELETE FROM artists
      WHERE id=$1
    SQL

    CONN.exec_params(sql, [self.id])
  end

  def albums
    sql = <<-SQL
      SELECT *
      FROM albums
      WHERE artist_id=$1;
    SQL

    CONN.exec_params(sql, [self.id]).to_a
  end
  binding.pry
end

# flim = Artist.new(nil, "Steven and the Flimflams")
# flim.save
#
# flim.name = "Steven and rockets"
# flim.save

# result = Artist.find_by_name("Steven and rockets")
# reunion = Artist.find(281)
binding.pry